This invention relates to a rotary sprinkler and, more specifically, to a rotary sprinkler having a stream interrupter driven in a step-wise, eccentric rotational manner by a rotating solid stream emitted from a fixed nozzle.
Stream interrupters per se are utilized in the sprinkling art for a variety of reasons. Representative examples as described in the patent literature are found in U.S. Pat. Nos. 5,192,024; 4,836,450; 4,836,449; 4,376,513; and 3,727,842.
One reason for providing stream interrupters is to insure uniformity of the sprinkling pattern. When irrigating large areas with sprinklers, the sprinklers need to be spaced as far apart as possible in order to minimize system costs. To achieve an even distribution of water at wide sprinkler spacings requires sprinklers that simultaneously throw the water a long distance and produce a pattern that "stacks up" evenly when overlapped with adjacent sprinklers. These two requirements are somewhat mutually exclusive in that maximum radius of throw is achieved with a single concentrated stream of water shooting at a relatively high trajectory angle (approximately 24.degree. from horizontal), but this stream by itself produces a "donut" pattern that doesn't stack evenly. Interrupting this concentrated stream, by fanning some of it vertically downwardly produces a more even pattern, but reduces the radius of throw.
The solution in accordance with this invention is to intermittently interrupt the stream so that at times, it is undisturbed for maximum radius of throw, and at other times it is fanned out to even out the pattern. To this end, the interrupter itself is moved in small rotational increments, so that the interruption points constantly move, thereby resulting in an even distribution of water around the sprinkler, and thereby precluding widely spaced dry "spoke" areas as would be left with a fixed interrupter.
Thus, in an exemplary embodiment of the invention, a self-stepping stream interrupter is provided which is designed for use in a sprinkler of the type where a stream is emitted in a substantially vertical direction from a nozzle fixed in the sprinkler body, which stream thereafter impinges on a groove formed in a rotor plate which redirects the stream radially outwardly. The groove in the rotor plate also has a circumferential component which causes the rotor plate to rotate about its center axis, which also passes through the nozzle. In the exemplary embodiment, the rotational speed of the rotor plate is slowed by a viscous fluid brake or dampener, so that the stream rotates at a speed of less than 20 rpm. In this way, both maximum throw and maximum stream integrity are achieved. Absent an interrupter, this arrangement would produce the so-called "donut" pattern described above.
In the exemplary embodiment, the rotor plate is supported on the viscous brake shaft which extends out of a brake housing supported within a sleeve or hub of the sprinkler cap assembly. The cap assembly is (removably) secured to the body of the sprinkler such that the rotor plate groove is located in vertically spaced relationship, and centered on the axis of the fixed nozzle.
The present invention seeks to take advantage of the maximum throw characteristics achieved by the relatively slow rotation of the rotor plate, and at the same time, to insure a uniform sprinkling pattern extending through a full 360.degree. radially between the sprinkler and the outermost portion of the sprinkling pattern.
In the exemplary embodiment described herein, a stream interrupter is provided which comprises an annular ring having a plurality of teeth extending radially inwardly from the inner surface of the ring. These interrupter teeth are adapted to partially engage a plurality of teeth formed on an exterior annular surface of the cap assembly hub which supports the rotor plate and associated viscous brake housing.
The interrupter in this exemplary embodiment is held loosely supported on a washer so that the interrupter can move axially in opposite directions, but not beyond the teeth on the cap assembly hub. At the same time, the minor diameter of the interrupter teeth is significantly larger than the minor diameter of the hub teeth, so that the interrupter is free to move in several directions, as well as rotationally, when struck by the stream coming off the rotor plate.
The interrupter is also provided with a plurality of depending stream interrupter fingers extending downwardly from the ring. These fingers are shaped as vanes, so that when a finger is struck by the stream, radial, circular, and tilting motions are imparted to the interrupter, as described in greater detail below.
The primary result of the oversized relationship of the interrupter vis-a-vis the hub, is that the interrupter is caused to "walk" around the hub in a step-by-step eccentric manner as the deflector fingers are struck, one at a time, by the stream emitted from the rotor plate. The vane configuration also deflects the stream sideways so that, as the stream rotates with the rotor plate, more and more of the pattern area is wetted so that, ultimately, a uniform sprinkling pattern is achieved throughout the full radial extent of the pattern.
Thus, in its broader aspects, the present invention relates to a sprinkler having a body portion including a nozzle, the nozzle adapted to emit a stream of liquid to atmosphere; first means for rotating the stream; a rotatable stream interrupter driven directly by the stream; and second means for causing intermittent rotation of the stream interrupter.
In another aspect, the invention relates to a sprinkler comprising a sprinkler body having a substantially vertical axis and means for throwing a liquid stream substantially radially relative to the vertical axis and rotating the liquid stream about the vertical axis, the improvement comprising a stream interrupter including an annular ring loosely mounted for eccentric rotation about the vertical axis, and wherein the stream drives the interrupter directly.
In another aspect, the invention relates to a sprinkler comprising a sprinkler body having a center axis and including a nozzle and associated first means for issuing a stream in a substantially radial direction, substantially perpendicular to the axis, and rotating the stream about the center axis; a stream interrupter mounted loosely for eccentric rotation about the center axis, the stream interrupter including an annular ring provided with a plurality of stream deflector fingers, the stream interrupter being driven directly by the stream impinging on the plurality of stream deflector fingers.
In still another aspect, the invention relates to a sprinkler having a fixed nozzle for emitting a stream to atmosphere; a rotor plate adapted to redirect the stream radially outwardly, the rotor plate caused to rotate about its own axis by the stream; and a stream interrupter having a plurality of stream interrupter vanes arranged to be struck by the stream as redirected by the rotor plate.
The invention also relates to a sprinkler having a fixed nozzle for emitting a stream to atmosphere; a rotor plate adapted to redirect the stream radially outwardly, the rotor plate caused to rotate about its own axis by the stream; and a stream interrupter loosely rotatably mounted on a hub, the interrupter having a plurality of stream interrupter vanes arranged to be struck by the stream as redirected by the rotor plate and rotated by the stream about the hub; and wherein the stream interrupter and the hub are provided with cooperating means for causing the interrupter to rotate in an eccentric step-wise manner about the hub.
The invention also relates to a sprinkler having a stationary body portion including a fixed nozzle, a rotatable rotor plate mounted in vertically spaced relationship to the nozzle, the rotor plate adapted to receive and redirect a stream emitted from the nozzle, the improvement comprising a hub having a first plurality of teeth formed on an external, annular surface thereof, and an annular stream interrupter loosely held on the hub and in surrounding relationship to the first plurality of teeth, the interrupter including a ring having a plurality of stream interrupting fingers arranged to be struck by the stream redirected by the rotor plate, the ring also having a second plurality of teeth formed on an interior annular surface thereof adapted for partial and progressive meshing with the first plurality of teeth to thereby cause the interrupter to orbit about the hub in a step-by-step, eccentric motion, as the fingers are successively struck by the stream.
While the stream interrupter of this invention is designed for use with a rotary sprinkler construction as described above, it will be appreciated that the stream interrupter may be applied to any rotary sprinkler that has a single concentrated emitting stream that rotates at a relatively slow speed.
Other objects and advantages of the invention will become apparent from the detailed description which follows.